Remove all harmony runtime flags which shipped in M51

src/parsing/scanner.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Features shared by parsing and pre-parsing scanners.
 
 #include "src/parsing/scanner.h"
 
 #include <stdint.h>
 
@@ skipping 1435 matching lines @@
       case 'g':
         flag = RegExp::kGlobal;
         break;
       case 'i':
         flag = RegExp::kIgnoreCase;
         break;
       case 'm':
         flag = RegExp::kMultiline;
         break;
       case 'u':
-        if (!FLAG_harmony_unicode_regexps) return Nothing<RegExp::Flags>();
         flag = RegExp::kUnicode;
         break;
       case 'y':
         flag = RegExp::kSticky;
         break;
       default:
         return Nothing<RegExp::Flags>();
     }
     if (flags & flag) return Nothing<RegExp::Flags>();
     AddLiteralCharAdvance();
@@ skipping 239 matching lines @@
     backing_store_.Add(static_cast<uint8_t>((one_byte_length >> 7) | 0x80u));
   }
   backing_store_.Add(static_cast<uint8_t>(one_byte_length & 0x7f));
 
   backing_store_.AddBlock(bytes);
   return backing_store_.EndSequence().start();
 }
 
 }  // namespace internal
 }  // namespace v8